Everybody knows biodiversity is important. But do you know exactly what it is, what it does, why it matters, why it is under threat and what you can do to protect it? If not then read on.
What is biodiversity?
Biodiversity is the total variation among living things in a given area. Biodiversity can be divided into a range of different levels, including species diversity and genetic diversity.
Species diversity refers to the number of different species in the area, but also takes into consideration the relative abundance of each species. The more equal the abundances of each species, the higher biodiversity is considered to be. Imagine a small wood with five hundred oak trees and one beech. Now imagine a wood with three hundred oaks and two hundred beech. The latter would be said to have higher species diversity than the former. When considering numbers of species alone and ignoring relative abundances, the term used is species richness. The two woods described above would have the same species richness. Species diversity is calculated from species richness and relative abundances using mathematical equations called diversity indices.
Genetic diversity refers to the amount of genetic variation in a single species. The details of genetic diversity are beyond the scope of this article, but again, distinctions exist between diversity and richness.
Why biodiversity matters
Biodiversity is important for many reasons, both to people and to the other species that make up ecosystems. Biodiversity is important to people, because it increases the ability of natural ecosystems to provide what are called ecosystem services. These include removing carbon dioxide from the atmosphere, and thus helping to reduce climate change, retaining water, and thus helping to avoid floods and droughts, and providing insects for pollinating crops. There are many other ecosystem services. Biodiversity increases an ecosystem's ability to provide ecosystem services because of complex interactions between species. These are disrupted when species are removed.
Biodiversity is important for the ecosystems and species of which they are comprised, because it enables them to adapt to changes and survive adverse conditions. The more species present, and the more genetic diversity in each species, the more likely it is that at least some individuals in at least some of the species will be able to survive in a changed environment, or will be able to resist a disease. For example, with more species present, it is more likely that some will be able to survive a warmer climate resulting from climate change. With more genetic diversity it is more likely that some individuals will be able to resist a disease. Thus English Elms were more vulnerable to Dutch elm disease because they were all genetically identical; they had zero genetic diversity. By extension biodiversity provides the raw material for natural selection and evolution. With greater diversity, there is more scope for species to evolve, adapting to change over time.
Biodiversity under threat
Humans are reducing biodiversity. This is because our activities are causing species to go extinct, and reducing the number of species, and the number of individuals in each species, which can survive in a given area. In fact, humans are causing so many species to go extinct that we may be causing the sixth mass extinction. As this suggests, there have only been five previous occasions in the history of life on Earth when so many species have gone extinct in such a short space of time.
Habitat destruction through development and urban expansion, climate change, pollution and over exploitation such as logging and over fishing are all contributing to species extinctions.
Genetic diversity is reduced when a species' numbers are reduced almost to the point of extinction. If the numbers increase again all the new individuals will be descended from a few individuals, meaning they will all be closely related. Another way to put this is that they will have very low genetic diversity. The time when there are very few individuals present is known as a genetic bottleneck. Another way genetic diversity is reduced is when habitats are isolated from one another, cutting off members of the same species and so reducing diversity in a given area.
How can we protect it?
In developed countries, legislation is starting to reduce the numbers of species extinctions. This is largely through tighter planning laws which require developers to determine the extent of ecological damage caused by a proposed development, and, if appropriate, create new habitat, move species, or alter the proposals to mitigate the damage.
However there are still more things we can all do to help. Planting native trees and creating other habitats such as ponds will help to provide habitats for a wide range of species. These and other activities can be done on a voluntary basis for a range of charities in the United States and many other countries. Many of the products we buy also have an impact on species diversity. For example timber and leather products may come from areas where illegal logging takes place, contributing to species extinctions. Always choose these products carefully, looking for independent certification of their sustainability.
Support Sustainable Brands
Support sustainable brands (like Fierce Hazel) that use eco-friendly business practices. Restaurants and co-ops with earth-friendly take-out packaging and fashion brands using deadstock or remnants to make their product.
The outside material of the Evolution Convertible Backpack is made from remnants that otherwise would be discarded. We use scraps discarded in the construction of another product that, in the past, were too small to use and sent to the landfill. We rescue those pieces and repurpose them for the exterior, main fabric.
Biodiversity is a measure of the variability of living things and can be divided into species diversity and genetic diversity. Biodiversity is important for maintaining ecosystem services for people and the ability of other species to adapt and survive. Biodiversity is being reduced by human activity but actions and choices we take can help to protect it.